Fixing tape

ABSTRACT

A plastics film having a two- or three-layer construction comprising a plastics film layer and a polymer blend layer formed on at least one side of the plastics film layer, one side of the polymer blend layer facing away from the plastics film layer being a satin surface.

FIELD OF THE INVENTION

This invention relates to a fixing tape for fixing a paper diaper, amedical instrument or the like to the human body.

BACKGROUND OF THE INVENTION

The applicant of the present invention has earlier proposed a film usedas a substrate for a tape for fixing a diaper to the human bodydescribed in JP-A-63-112704. (The term "JP-A" as used here in means anunexamined published Japanese patent application). This conventionaltape substrate is made of a blend of one or more of an ethylene-vinylacetate copolymer, a polyethylene and an ethylene-propylene copolymerwith a polypropylene, the polypropylene content being 5 to 75 wt. %.This conventional diaper-fixing tape, used in direct contact with theskin of the baby or infant, has been proposed in view of the handle ordrape and the softness in an attempt to prevent the baby skin from beingsubjected to a rash, redness and a laceration. However, thisconventional tape substrate has been found not entirely satisfactory inthat it is a little rigid. This difficulty arises out of the fact thatthe processability encountered when producing the tape has been takeninto account.

Tests of this conventional diaper-fixing tape by monitors have indicatedthat a rash and a laceration have not appeared on the skin, but theredness on the skin has not been improved sufficiently.

SUMMARY OF THE INVENTION

With the above deficiencies of the prior art in view, it is an object ofthe present invention to provide a fixing tape best suited for fixing adiaper or other medical instrument to the skin of the human body whichtape has a good drape or handle, and is so soft as not to irritate ordamage the skin, and can be easily held between the fingers, and lookssoft and gives a high-quality impression.

The above and other objects and effects of the present invention will bemore apparent from the following description.

According to the present invention, there is provided a fixing tapecomprising a plastics film having a two- or three-layer constructioncomprising a plastics film layer and a polymer blend layer formed on atleast one side of the plastics film layer, one side of the polymer blendlayer facing away from the plastics film layer being a satin surface.

An adhesive layer may be provided on at least one surface of theplastics film by applying an adhesive agent. On the portion of thesurface of the plastics film where the adhesive layer is not provided, aback face treating layer may be provided for facilitating the release ofan adhesive layer of another fixing tape and the prevention of rubbingor sticking of other materials to be in contact with the fixing tape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(a1) and 1(a2) each is a cross-sectional view of a fixing tapeprovided in accordance with one embodiment of the present invention; and

FIGS. 1(b) to 1(d) are cross-sectional views of fixing tapes provided inaccordance with another embodiments of the present invention.

FIG. 2 is a front-elevational view of a diaper using the fixing tapes ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

The inventors of the present invention have made an extensive study inan attempt to obtain a diaper-fixing tape which is gentler or softer tothe skin, and found that the fixing tape of the above construction hasincreased softness and handle or drape. Since the tape has the satinsurface, the tape can be easily held by the fingers because of a highcoefficient of friction of the satin surface, and thereby facilitatingthe fixing of the diaper to the skin. Further, the satin surface doesnot have a gloss, which gives a high-quality impression.

If the tape substrate is merely made solely of a film of polyethylene orpolypropylene, or a film of an ethylenevinyl acetate copolymer or anethylene-propylene copolymer, which have a good handle or drape, thefollowing disadvantages are encountered:

(1) Since the surface of the film is smooth, a release agent is liableto be removed by friction.

(2) Most of such films has a poor reactivity with a silicone used as aback face treating agent.

(3) The film is too soft and has no nerve.

(4) The film made of polypropylene is liable to be torn.

The fixing tape of the present invention has the satin surface, andtherefore the removal of a back face treating agent is prevented, andalso the reactivity with silicone is improved. (Of course, the satinsurface must be free from an antioxidant and a metal which restrict thereaction with silicone.) Further, the plastics film is of a two- orthree-layer laminated construction, that is the upper layer or the upperand lower layers are laminated with the polymer blend layers having thestain surface. With this construction, the fixing tape of the presentinvention is sufficiently soft but has an increased nerve, and can notbe torn easily. Therefore, the fixing tape is best suited for fixing adiaper or other medical instrument to the human body, since the fixingtape can be freely flexed following the motion of the human body.

If the satin surface like those in the present invention is intended tobe formed after fabricating the plastics film, the use of sandblast or atextured roll is required. This is undesirable since it increases thenumber of process steps and hence increases the cost. However, in thepresent invention, the laminated film comprising the satinized polymerblend layer and the plastic film layer of a good handle or drape can beobtained by a simultaneous molding method. Therefore, the fixing tape ofthe present invention can be produced at low costs.

The fixing tapes of the present invention will now be described withreference to the drawings.

FIGS. 1(a1) and 1(a2) each shows a fixing tape A according to thepresent invention. The fixing tape A comprises a plastics film layer 2,and a polymer blend layer 1 formed on one side of the plastics filmlayer 2. An adhesive layer 3 is provided on the other side of theplastics film layer 2. In the embodiment in FIG. 1(a2), the plasticsfilm layer 2 is composed of two layers 2a and 2b. The polymer blendlayer 1 has an outer surface which is satinized. A release agent layeror back face treating layer 4 is optionally formed on the satinizedsurface of the polymer blend layer 1.

FIGS. 1(b) to 1(d) show modified fixing tapes A1 to A3 according toanother embodiments of the present invention.

In the fixing tape A1 of FIG. 1(b), a pair of polymer blend layers 1 and1' are formed respectively on the opposite sides of the plastics filmlayer 2, each polymer blend layer having an outer satinized surface asdescribed above in the preceding embodiment. The adhesive layer 3 isformed on the satin surface of the lower polymer blend layer 1'. Arelease agent layer or a back face treating layer 4 is formed on thesatin surface of the upper polymer blend layer 1.

In the fixing tape A2 of FIG. 1(c), the pair of polymer blend layers 1and 1' are formed respectively on the opposite sides of the plasticsfilm layer 2, as described above for the fixing tape A1 of FIG. 1(b). Apair of upper and lower adhesive layers 3 and 3' of a smaller width areformed respectively on the stain surfaces of the upper and lower polymerblend layers 1 and 1'. More specifically, the upper adhesive layer 3 isformed on a generally half width of the satin surface of the upperpolymer blend layer 1. The lower adhesive layer 3' is formed on agenerally half width of the stain surface of the lower polymer blendlayer 1'. The upper and lower adhesive layers 3 and 3' are disposedgenerally asymmetrically with respect to the longitudinal axis orcenterline of the fixing tape A2. In the illustrated embodiment, each ofthe upper and lower adhesive layers 3 and 3 has a width greater than ahalf of the width of the fixing tape A2. The portions of the satinsurfaces of the polymer blend layers 1 and 1, where the adhesive layers3 and 3' are not provided are provided with the release agent layer orthe back face treating layer 4.

In the fixing tape A3 of FIG. 1(d), the pair of polymer blend layers 1and 1' are formed respectively on the opposite sides of the plasticsfilm layer 2, as described above for the fixing tape A1 of FIG. 1(b). Anadhesive layer 3' is formed on a generally half of the satin surface ofthe lower polymer blend layer 1'. Adhesive layers 3 and release agentlayers or back face treating layers 4 are formed alternately andpatternwise on the satin surface of the upper polymer blend layer 1.Alternatively, both the satin surfaces of the polymer blend layers 1 and1' may be provided with the adhesive layers 3 and 3' and the releaseagent layer or the back face treating layers 4 formed alternately andpatternwise.

FIG. 2 shows a diaper B to which fastener tapes comprising the fixingtapes of the present invention are attached. Reference character Adenotes a fastening tape, reference character C denotes a release tape,and reference character D denotes a reinforcing film. The fixing tape Aand A1 of FIGS. 1(a1), 1(a2) and 1(b) can be used as the fastening tapeA and the reinforcing film D.

The plastics film layer 2 of the fixing tape of each of the aboveembodiments has a good handle or drape. The plastics film layer 2 can bemade of any one or mixture of a polyethylene, a polypropylene, anethylene-vinyl acetate copolymer and an ethylene-propylene copolymer.The plastics film layer 2 preferably has a width direction compressionstrength of 200 g/mm² or less, and more preferably from 40 to 100 g/mm².By using the plastics film layer having a width direction compressionstrength within the above range, a fixing tape having appropriatesoftness and nerve can be obtained.

The "width direction compression strength" used herein is determined bythe following manner: the plastics film sample (65 mm×25 mm) is made aloop (diameter: 20 mm) by looping in the longitudinal direction; theloop is placed on a plate and pressed in the width direction at 23° C.,65% RH at a rate of 10 mm/min; the maximum pressing force at which theloop starts to collapse is divided by the thickness of the plastics filmsample to obtain the width direction compression strength.

Preferred examples of the material for the plastics film layer 2 includean ethylene/vinyl acetate copolymer having a vinyl acetate content of 4%or more, a very low density polyethylene (VLDPE), a low densitypolyethylene (LDPE), a linear low density polyethylene (L-LDPE), aethylene/propylene copolymer having a ratio of ethylene/propylene offrom 9/1 to 1/9, and a chlorinated polypropylene, as well as a mixtureof a polypropylene with at least one of a polyethylene, anethylene/propylene copolymer and an ethylene/vinyl acetate copolymerhaving a ratio of the polypropylene to the other resins of from 0/10 to9/1, more preferably from 4/6 to 6/4.

The polymer blend layer 1, which is formed on at least one side of theplastics film layer 2 and has the satin surface, can be made of apolymer blend comprising at least two resins selected from the groupconsisting of an ethylene-vinyl acetate copolymer, an ethylene-propylenecopolymer and a polyethylene. It is preferred that the polymer blendlayer 1 be made of a polymer blend composed of at least one of apolyethylene and an ethylene/propylene copolymer with a polypropylene,the polypropylene content being 5 to 95 wt. %, more preferably 5 to 75wt. %. In this case, a low-density polyethylene film is preferably usedas the plastics film layer 2. A mixture of a polypropylene and apolyethylene having a polypropylene content of 75 wt. % is mostpreferred for the polymer blend layer.

The thickness of the plastics film composed of the polymer blend layer 1and the plastics film layer 2 is usually from 1 μm to 1 mm, but is notlimited to such thickness. The thickness of the polymer blend layer 1 ispreferably from 3 to 5 μm, and the thickness of the plastics film layer2 is preferably from 30 to 200 μm.

Such a plastic film is preferably obtained by a simultaneous extrusionmolding method using a T-die.

An adhesive agent of which the adhesive layer 3 is made is notparticularly limited, and the adhesive layer 3 may be made of a knownadhesive agent such as an acrylic type adhesive agent, a rubber typeadhesive agent and a styrene type adhesive agent. The thickness of theadhesive layer 3 is usually from 5 to 500 μm, but is not limited to suchthickness.

The back face treating layer can be formed by using any conventionalmethods and materials, and is preferably formed by coating a silicone ora long-chain alkyl release coating agent.

The present invention will now be illustrated by referring to thefollowing Examples and Comparative Examples, but the present inventionis not construed as being limited thereto.

EXAMPLES

Various films having a two- or three-layer construction were preparedusing various polymers shown in Table 1. The films of a two- orthree-layer construction were formed by a simultaneous extrusion moldingmethod using a T-die, the temperature of the die being 180° C. Then, astyrene-type adhesive agent was applied to one side of each of the thusprepared films to form an adhesive layer having a thickness of 50 μm,thereby providing fixing tapes. In the samples of Example 1, 2 and 4,the adhesive layer is formed on the intermediate layer; and the sampleof Example 3, the adhesive layer is formed on the lower layer. Varioustests, which include the handle or drape (softness), the nerve and thereactivity with silicone as a back face treating agent, of the thusobtained fixing tapes were carried out, and the results of the tests andtotal evaluation are shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________                                    Comparative                                              Example              example                                                  1    2   3      4    1   2    3                                    __________________________________________________________________________    Polymer composition                                                           Upper layer                                                                              PE/PP                                                                              PE/PP                                                                             PE/E-P/PP                                                                            EVA/PP                                                                             --  --   --                                              30/70                                                                              70/30                                                                             30/10/60                                                                             30/70                                              Intermediate layer                                                                       L-LDPE                                                                             PP  L-LDPE EVA  EVA L-LDPE                                                                             PP                                   Lower layer                                                                              --   --  PE/E-P/PP                                                                            --   --  --   --                                                       30/10/60                                                  Layer thickness (μm)                                                       Upper layer                                                                              20   20   10     50  --  --   --                                   Intermediate layer                                                                       80   40  130    150  200 100  60                                   Lower layer                                                                              --   --   10    --   --  --   --                                   Total thickness                                                                          100  60  150    200  200 100  60                                   Test results                                                                  Handle or drape                                                                          10/10                                                                              9/10                                                                              8/10   9/10 9/10                                                                              10/10                                                                              0/10                                 (softness)                                                                    Nerve (mm)  2    8  0-1    3-5  20-25                                                                             15-20                                                                              6-8                                  Reactivity with                                                                          A    A   A      A    C   C    C                                    silicone                                                                      Overall evaluation                                                                       A    B   A      A    C   C    C                                    __________________________________________________________________________     Note:                                                                         PE: Polyethylene (V141; manufactured by Nippon Oil Company, Ltd.)             PP: Polypropylene (J350G; manufactured by Nippon Oil Company, Ltd.)           EP: Ethylenepropylene copolymer (Tafmer P0680; manufactured by Mitsubishi     Oil Co., Ltd.)                                                                EVA: Ethylenevinyl acetate copolymer (H616-3; manufactured by Mitsubishi      Oil Co., Ltd.)                                                                LLDPE: Lowpressure lowdensity polyethylene (Ultzex 3010F; manufactured by     Mitsubishi Oil Co., Ltd.)                                                     LDPE: Lowdensity polyethylene (V141N; manufactured by Nippon Oil Company,     Ltd)                                                                     

The evaluation in the above Table 1 was conducted in the followingmanner:

1. Handle or drape (softness): Organoleptic tests by ten monitors wereconducted to determine the feeling through the eyes and the feelingthrough contact with the skin. The results were indicated in terms ofthe number of the monitors who determined the sample having good handleor drape per the total number of the monitors.

2. Nerve: Each fixing tape was adhesively bonded to a polyester plate ofwhich back face was treated by a long-chain alkane at 23° C., 65%RH andpressed twice with a 2 kg roller, and after 30 minutes, the fixing tapewas peeled at a rate of 300 mm/min. The tape was placed on a flat platesuch that the concave of the tape was made upward. The nerve wasdetermined by checking the degree of curling in terms of theperpendicular distance between the plate and the edge of the tape.

3. Reactivity with silicone: Silicone (X-62-1148; manufactured byShin-etsu Silicone Co., Ltd.) was coated on the upper layer (Examples 1to 4) or the intermediate layer (Comparative Examples 1 to 3) of eachsubstrate in an amount of 0.5 g/m², and then the substrate was heatedfor 30 seconds at 100° C. Subsequently, the silicone coated layer wasrubbed once with the finger to check the degree of curing of thesilicone coating. Thereafter, the silicone-coated film was furtherrubbed five times with the finger, and then a lipophilic ink was coatedon the film to see how the lipophilic ink was coated thereon, thusjudging the degree of removal of the silicone from the film. If the inkformed cissings, the silicone remained and the reactivity was evaluatedas good (A). If the ink was uniformly coated, the silicone was removedby rubbing and the reactivity was evaluated as poor (C).

4. Overall evaluation: The suitability of the samples for a fixing tapefor fixing a diaper or a medical instrument to the human body wasevaluated in view of the results of the tests 1 to 3 above. Theevaluation was made in terms of excellent (A), good (B), and poor (C).

As is clear from the above Table 1, it has been recognized that thefixing tapes of the present invention used as a fastener tape for adiaper is hardly irritating to the skin, and has sufficient softness andnerve, so that the fixing tape material is very practical and a goodprocessability.

Therefore, the fixing tapes of the present invention can be suitablyused not only as a diaper fixing tape but also as a tape for fixing amedical instrument to the human body.

While the invention has been described in detail and with reference tospecific examples thereof, it will be apparent to one skilled in the artthat various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A fixing tape comprising:a plastic film layer; afirst polymer blend layer formed on one side of said plastic film layer,where the side of said first polymer blend layer facing away from saidplastic film layer has a satin surface; an adhesive layer provided on atleast one portion of the side of said satin surface of said firstpolymer blend layer, and a release agent layer formed on the oppositeside of said plastic film layer from said first polymer blend layer. 2.A fixing tape as claimed in claim 1, wherein said plastic film layercomprises two or three layers.
 3. A fixing tape as claimed in claim 1,wherein said plastic film layer is made of a polymer chosen from thegroup consisting of polyethylene, polypropylene, ethylene-vinyl acetatecopolymer, and ethylene-propylene copolymer.
 4. A fixing tape as claimedin claim 1, wherein said polymer blend layer is made of a polymer blendcomprising at least two resins selected from the group consisting of anethylene-vinyl acetate copolymer, an ethylene-propylene copolymer, and apolyethylene.
 5. A fixing tape as claimed in claim 1, wherein saidpolymer blend layer is made of a polymer blend composed of at least onepolymer chosen from the group consisting of a polyethylene and anethylene-vinyl acetate copolymer; combined with a polypropylene, whereinsaid blend layer contains from 5 to 95 wt. % polypropylene.
 6. A fixingtape as claimed in claim 5, wherein said plastic film layer is made of alow density polyethylene.
 7. A fixing tape as claimed in claim 1 whereinsaid release agent layer is made of silicone.
 8. A fixing tapecomprising:a plastic film layer; a first polymer blend layer formed onone side of said plastic film layer, where the side of said firstpolymer blend layer facing away from said plastic film layer has a satinsurface; a second polymer blend layer formed on the opposite side ofsaid plastic film layer from said first polymer blend layer, where theside of said second polymer blend layer facing away from said plasticfilm layer has a satin surface; and an adhesive layer provided on atleast one portion of at least one side of said first or second polymerblend layer.
 9. A fixing tape as claimed in claim 8, furthercomprising:an adhesive layer provided on said satin surface of saidfirst polymer blend layer, and a release agent layer provided on saidsatin surface of said second polymer blend layer.
 10. A fixing tape asclaimed in claim 8, wherein a release agent layer and said adhesivelayer are alternately formed in a pattern on said first and secondpolymer blend layers.
 11. A fixing tape as claimed in claim 8, whereinsaid plastic film layer comprises two or three layers.
 12. A fixing tapeas claimed in claim 8, wherein said plastic film layer is made of apolymer chosen from the group consisting of polyethylene, polypropylene,ethylene-vinyl acetate copolymer, and ethylene-propylene copolymer. 13.A fixing tape as claimed in claim 8, wherein said polymer blend layer ismade of a polymer blend comprising at least two resins selected from thegroup consisting of an ethylene-vinyl acetate copolymer, anethylene-propylene copolymer, and a polyethylene.
 14. A fixing tape asclaimed in claim 8, wherein said polymer blend layer is made of apolymer blend composed of at least one polymer chosen from the groupconsisting of a polyethylene and an ethylene-vinyl acetate copolymer;combined with a polypropylene, wherein said blend layer contains from 5to 95 wt. % polypropylene.
 15. A fixing tape as claimed in claim 14,wherein said plastic film layer is made of a low density polyethylene.16. A fixing tape as claimed in claim 8, wherein a release agent layerand said adhesive layer are alternately formed in a pattern on saidfirst and second polymer blend layers.
 17. A fixing tape as claimed inclaim 16 wherein said release agent layer is made of silicone.